Sex determination of human remains from peptides in tooth enamel

The assignment of biological sex to archaeological human skeletons is a fundamental requirement for the reconstruction of the human past. Determining the sex of human remains has implications ranging from the archaeological to legal contexts. DNA sequencing can be used for sex determination, but the approach is expensive, time-consuming, and depends on the quality of the DNA sample.

Dr Nicolas Stewart at the University of Brighton, together with colleagues at Durham University and the University of Sao Paulo, have developed a method for the sex determination of human remains using peptides from tooth enamel, the most durable human body tissue. To extract peptides from tooth enamel, the method uses a minimally destructive acid-etch procedure. Subsequently, sex chromosome-linked isoforms of amelogenin – an enamel-forming protein – are identified from the acid-etch sample using nano-liquid chromatography mass spectrometry. The researchers tested the method in studies on the remains of seven adult individuals from the late nineteenth century as well as male and female pairs from three archaeological sites ranging from 5700 years ago to the sixteenth century in the United Kingdom. In each context, the method successfully determined the sex of the individuals, as confirmed by comparison with coffin plates or standard osteological analyses.

Photo credit: Jeff Veitch from Durham University

Project timeframe

This project commenced in 2014 and is ongoing.

Project aims

The project aims were to refine a method using mass spectrometry to characterise peptides from tooth enamel and to correctly ascertain the sex from human remains using this method.

Tooth enamel is the hardest tissue in the human body and survives burial exceptionally well, even when the rest of the skeleton or DNA has decayed. This new method can reliably determine the biological sex of humans of any age using a body tissue that is difficult to cross-contaminate and is most likely to survive and will make sex determination of adults and, for the first time, juveniles a reliable and routine activity in future.

The method has potential implications for improving techniques for sex determination of human remains, and might have applications relevant to bioarcheaology, paleoanthropology and medical-legal science.